Blooms of bryozoans and epibenthic diatoms in an urbanized sandy Beach (Balneário Camboriú - SC - Brazil): dynamics, possible causes and biomass characterization

Abstract

Balneário Camboriu (SC - Brazil) is a touristic city where the disordered growth of the urban population and the implementation of coastal works without proper evaluation generated environmental impacts and affected the sanitary quality of water and sediment of Camboriu River and marine adjacent area. One of the most recent and alarming phenomena observed are the blooms of invasive bryozoans (Arboscuspis bellula and Membraniporopsis tubigera) associated with epibenthic diatoms (Amphitetras antediluviana and Biddulphia biddulphiana). Several clues associate these phenomena, started in 2003, with the excess of nutrients and organic matter in the Camboriú cove and large coastal works such as dredging, landfills and construction of jetties, leading to changes in benthic ecological structure. Being an aesthetic and environmental health problem, the concern of the scientific community and government agencies intensified as the occurrences become more frequent and persistent. This research addresses this issue through environmental and experimental studies. Samplings of the benthic material collected by boat and diving, and blooms monitoring were the environmental approach. The laboratory work included the algal isolation and culture, in addition to growth conditions assessment and chemical biomass analysis. Monitoring data showed a seasonal trend in the blooms, with more conspicuous events in warmer months. Diatoms increase in abundance in colder months and bryozoans in the warmer ones. The diatom A. antediluviana, predominant in the blooms, grew satisfactorily in laboratory cultivation, showing better growth in media with higher concentrations of silicate and phosphate. Bryozoans showed slow growth in laboratory conditions. The deposited material collected in the environment showed low concentrations of saturated fatty acids, but the high biomass suggest a possible use for biofuels production. Biomass samples dominated by bryozoans showed moderate antimicrobial activity against Klebsiella pneumoniae. The explanation for the occurrence of these blooms are still inconclusive, but there is considerable evidence that it is a synergistic effect between the high concentration of bacteria and organic debris in the water related to local pollution and the elimination of natural competitors by coastal works.

Relationships between benthic infauna and groundwater eutrophication on a sandy beach in southern Brazil

“…The nitrogen cycle relies on the intense participation of bacteria in the nitri cation process, with the bacterial oxidation of ammonia (NH 3 ) to nitrite Balneário Camboriú, Santa Catarina. There was an increase in concentrations of nutrients in the water column in the summer that promoted considerable growth of bryozoans and phytobenthos (Rörig et al 2017), which are an important source of food for the polychaete T. furcifera (Otegui et al 2012). In this sense, and because it is in a more sheltered place on the coast, Enseada Beach predominantly has sediment with ne sand, which contributes to the population growth of T. furcifera in the summer, a pattern also found by Barros Another important association related to an increase in the total density and richness of the infauna comprises S. goodbodyi, D. hanleyanus, H. olivieri, H. cinerea and Haploscoloplos sp.…”

Nutrient enrichment stimulates herbivory and alters epibiont assemblages at the edge but not inside subtidal macroalgal forests

“…Filter-feeders can benefit from nutrient enrichment via increased availability of plankton and organic particles. Such effects are common at sites exposed to sustained nutrient inputs (Gili and Coma 1998;Prado et al 2010a;Rorig et al 2017). Nutrients may have also enhanced the quality of epizoans as food.…”

Mosdiertjes problematiek in Nederlandse kustwateren : onderzoek naar de verspreiding voor de Nederlandse kust en de problemen die het veroorzaakt in de visserij en mogelijke mitigerende maatregelen

“…Interessant gegeven daarbij is dat ook daar de massale strandingen zeer lokaal zijn en in gelijkenis met de massale bloei in Nederland, de mosdiertjes ook problemen veroorzaken voor de visserij. Naar aanleiding van deze waarnemingen is in Brazilië een uitgebreid aanvullend onderzoek opgezet naar de mogelijke oorzaken en verspreiding van het probleem(Rörig et al 2017). Zij schrijven onder meer dat er een verband tussen epibenthische diatomeeën (microscopische kiezelwieren die op de bodem leven) en de massale bloei van deze mosdiertjes is Rörig et al (2017).…”

“…Naar aanleiding van deze waarnemingen is in Brazilië een uitgebreid aanvullend onderzoek opgezet naar de mogelijke oorzaken en verspreiding van het probleem(Rörig et al 2017). Zij schrijven onder meer dat er een verband tussen epibenthische diatomeeën (microscopische kiezelwieren die op de bodem leven) en de massale bloei van deze mosdiertjes is Rörig et al (2017). omschrijven een gedragsverandering van de beide soorten A. bellula en M. tubigera.…”